This invention relates to an illuminated sign having selected indicia lighted by means of a plurality of LED's which may be conventional encapsulated LED's or LED dices. In particular, the invention relates to a sign having LED's which provide a single colored informational message in a normal state, and a red color flashing message in an emergency state.
Lighted signs bearing certain indicia, such as numbers or letters, are well known and used for a variety of purposes. Lighted signs which may indicate the house number of a residence, and which may be also used in case of emergency, are disclosed in Lazar, U.S. Pat. No. 3,360,791, Clardy, U.S. Pat. No. 3,599,201, and Browand, U.S. Pat. No. 4,003,040. Indicia on the face of these signs indicate the street number of the residence, and an emergency signal including a flashing red light is also provided to alert passersby of an emergency situation. Klingenberg, U.S. Pat. No. 3,913,092, discloses an alert sign mountable in a window having a HELP message illuminated by a flashing incandescent bulb. This type of warning device is useful for informing persons outside of a house of the plight of an ill person in the house. It is also known to use LED's in lighted signs; for example, Okuno, U.S. Pat. No. 4,298,869, discloses road signs and traffic lights using LED's.
Lighted signs bearing variable indicia, such as numbers or letters, may be useful for many purposes, including the indication of street numbers of residences, message signs in care centers, hospitals, restaurants, or any other enclosed environment which requires transmission of an illuminated message. The present invention contemplates a multi-purpose lighted sign which consists of a plurality of rows of lighted LED's which are selectively illuminated to form desired indicia. The display is preferably a conventional seven-segment, block figure "8", in which the segments can be illuminated to depict any number from 0-9. The sign is formed from a plurality of light display modules, thus enabling the sign to display a multi-digit number. If desired, the sign may be configured to show letters instead of, or in addition to, numbers.
The indicia are illuminated by straight rows of a plurality of low-voltage light-emitting diodes (LED's) which can be preset to send a desired message or display a specific number. Thus, a homeowner would set the proper switches upon purchase of the unit to display the correct house number permanently. Optionally, the sign may be linked to a number of useful features, such as a remote radio actuator and a photocell to turn the sign on when the light intensity decreases below a preset level. A particularly important feature of the invention is for the lighted portion of the sign to change from one color to a different color (e.g., from green to red) in an emergency situation. By using existing LED technology which enables the same LED to illuminate in different colors with different applied voltages, the sign can read in either an emergency or normal mode without losing any brightness. This is very important for LED's, which individually have a relatively low power level. A flashing mechanism in the sign circuitry enables the LED's to flash intermittently when the sign is in the emergency mode. In addition, actuation of the emergency mode may also activate any of a number of alarm systems, including an audible alarm such as a bell or whistle, or transmission of an alert signal off the premises (e.g., by telephone line) to a guard gate, police department, fire department, hospital, or the like. The emergency switch may be actuated either manually, remotely by a radio transmitter, or by some other automatic mechanism such as a smoke detector.
The use of LED's to illuminate the sign of the invention is advantageous since they require only a low-voltage (5-10 v) DC power source. Installation is very safe and does not require ducting as is required by most construction codes. In addition, the low voltage LED's have a much longer life expectancy than neon or incandescent illuminating devices. Power consumption is very low, yet light intensity is sufficiently high to enable the sign to be seen from a distance of up to 250 feet away (depending on ambient lighting conditions). Furthermore, maintenance and operating costs are very reasonable compared with other lighted signs. Accordingly, it is an object of the present invention to provide a lighted sign illuminated with LED's which is visible to a distance of several hundred feet, yet which uses a low voltage power source and is inexpensive and safe to operate. It is yet another object of the invention to provide a lighted sign which can change color from green to red in an emergency situation without losing visibility. It is yet a further object of the invention to provide an LED-illuminated sign which can be remotely actuated, and which itself can actuate remotely receivable alarm systems in an emergency situation. These and other objects are accomplished by the illuminated sign of the invention, a specific embodiment of which is described herein.